Method of treating leather and product thereof.



W. E. SMITH. METHOD OF TREATING LEATHER AND PRODUCT THEREOF.

APPLICATION FILED MAY 28, 1910.

1,025,324. Patented May 7, 1912.

' UNITED STATES PATENT OFFICE.

WILLIAM R. SMITH, OF BUFFALO, NEW YORK, ASSIG-NOR TO BUFFALO LEATHER 00., OF BUFFALO, NEW YORK, A CORPORATION OF WEST VIRGINIA.

Application filed May 28, 1910. Serial No. 563,931.

Specification of Letters Patent.

Patented May 7, 1912.

To all whom it may concern:

Be it known that I, WILLIAM R. SMITH, of Buffalo, in the county of Erie and State of New York, have invented a certain new and useful Method of Treating Leather and Product Thereof, of which the following is a specification.

The object of this invention is to render leather more durable, more waterproof,- and in the case of heavy leather more resistant to surface slipping, and stiffer while retaining its original resiliency. These improved qualities are retained at all temperatures at which the articles manufactured from such leather are likely to be subjected to in regular use.

My object I accomplish by stufling, that is, by filling the pores of the leather with a bituminous composition having the desired qualities. I introduce the bituminous composition by bringing the leather in contact therewith at a temperature high enough to render the composition thin and fluid, and not high enough to injure the leather. The maximum temperature varies with the kinds of tannage, the vegetable-tanned resistinga temperature of 150 F., and chrome up to about 200 F. To insure proper imregnation, the leather should be dry and ree from oils, glucose, etc. I prefer to treat the leather in a rotary tumbling drum, the fluid mixture and the heated soles being introduced into the drum which is steamjacketed and heated so that the temperature of the air within it is somewhat above the melting point of the said mixture, the drum being preferably provided with radial inwaroly projecting shelves adapted, when the drum is rotated, alternately to raise and release the composition and the pieces of leather contained in the drum. This operation is continued until the composition thoroughly permeates the leather, the permeation being facilitated by the agitation .and percussion due to the rotation of the drum. The leather employed is preferably of a orous character such as chrome-tanned sole eather. g

My invention is not limited to the employment of a tumbling drum. The soles may be immersed or suspended in the body of the heated com sition for a suitable length of time instea of being placed with the composition in a tumbling drum. I prefer the tumbling operation, however, as more expeditious and convenient. The tumbling operation is also preferred because it insures freedom from prolonged contact between the soles during impregnation, it being a fact that a prolonged contact between two soles such as would occur if the soles were held stationary while being impregnated, one sole bearing against another, will prevent the contacting parts from being suitably impregnated.

The accompanying drawing, forming a part of this specification, shows in section and somewhat diagrammatically, a rotary tumbling drum of which a is the steam jacket which is preferably extended to cover the ends or heads of the drum. 0, 0 indicate the shelves.

f indicates an opening for the insertion of the soles and the composition, and for the removal of the soles, sald opening having a suitable closure 9. The drum may be supported by rolls h, h mounted to rotate 1n fixed bearings. 4

I may treat whole sides, but preferv for economy ofthe impregnating composition to tumble the leather and composition after cutting the leather into blanks or forms of ap roximately the final size.

s the composition of the impregnating mixture and the temperature are both fao tors in fixing the time of complete penetration, this can be best determined by actual trial, but ordinarily the process is completed within one-half hour.

The bituminous composition used by me contains as essential components a solid bitumen possessing, at normal or somewhat higher temperatures, a considerable degree of elasticity, combined with a bitumen which, in its fused condition possesses marked penetrative powers. The variety of elastic bitumen preferred is elaterite or mineral rubber and the variety of penetrative bitumen preferred is ozocerite. While the mineral elaterite is greatly to be desired insuch a composition, its use has been prevented by its infusible and insolu-v ble character, and its viscosity when brought into a state of fusion by admixture with other bitumens. This diificulty I overcome by altering the character of the elaterite so as to render'it easily soluble in melted ozocerite or equivalent paraflin. I find that when elaterite is gradually added to a melted bitumen, such. as gilsonite, which is capable of withstanding a high degree of heat without decomposition, the elaterite is softened and gradually dissolved, and thus an indefinitely large quantity of elaterite can be melted in the presence of a small quantity of gilsonite.

The elaterite fusible at high temperature without decomposition and soluble in hot paraffins' and forming therewith a thin penetrating liquid, is herein termed modified elaterite. Whether this quality is obtained artificially, as described, or by selection in natural elaterites, which are known to differ considerably from one another in resistance to heat and other characteristics, the same designation applies.

An example of modified elaterite is the so-called kapak, a bitumen well known in the trade and produced from elaterite by means unknown to me. The elaterite found in Utah, U. S. A., has all the desired qualities for the practice of my invention. 'It is non-friable, tenacious, only moderately brittle at low temperatures, elastic at normal temperatures, resilient, and resistant chemical alteration. When slightly warmed it becomes more flexible, and more elastic so that if drawn out or bent, it (like rubber) tends to return to its former shape upon the release of the disturbing force. When raised to a high temperature it undergoes destructive distillation and carbonization without melting. I may, by fusion with a solid parafiin body, bring it partly into solution; but I prefer to render it substantially soluble in melted solid paraflin by previous-modification. Ozocerite, having a higher melting point than ordinary solid parafiin, I find to be a superior ingredient in my special composition. The' proportion of pafrafi in to modified elaterite w1ll naturally vary somewhat according to the specific qualities given the latter. I find three parts of ozocerite to one of modified elaterite to be generally suitable.

The flexibility and resiliency of elaterite I find to be measurably retained by the above composition, and in addition it possesses a surface frictional resistance such as is possessed by beeswax. The value of the latter quality is clearly observed when chrometanned sole leather is stuffed with my material. Notwithstanding the durable character of chrome leather, itsuse for the soles of shoes has-been greatly limited by the slipperiness of this leather in wet weather. When chrome leather is impregnated with my material, this undesirable quality is effectually overcome. The wearing qualities of heavy leather of all kinds for use for soles or heels is greatly increased by this treatment. When finished leather filled with ordinary paraffin wax is placed in hot sunshine or near a stove, there is a strong tendency for the Wax to melt and exude, thus defacing the shoe or other article. On ac: count of the viscosity and high melting point of my preparation, the leather is not injured by any similar elevation of temperature.

I claim:

1. The process of waterproofing and stiffening leather and imparting non-slipping qualities thereto, which consists in immersing the leather in a' heated, fluid mixture containing a solid bitumen possessing at normal or somewhat higher temperatures a degree of elasticity comparable to that of elaterite, and a fusible bitumen possessing high penetrative qualities.

2. The process of waterproofingand stiffening leather and imparting non-slipping qualities thereto, which consists in immersing the leather in a heated, fluid mixture containing elaterite, combined with a fusible bitumen possessing high penetrative qualities..

3. The process of waterproofing and stiffening leather and impartin non-slipping qualities thereto, which consists in immersing the leather in a heated, fluid mixture containing elaterite combined with ozocerite.

4:. The process of waterproofing and stiffening leather and imparting non-slipping qualities thereto, which consists in immersing the leather in a heated, fluid mixture containing elaterite, modified to render it substantially soluble in liquefied parafiin, combined with a fusible bitumen possessing high penetrative qualities.

5. The process of waterproofing and stiffening leather and imlparting non-slipping qualities thereto, whic consists in immersing the leather in a heated, fluid mixture containing elaterite, modified to render it substantially soluble in liquefied parafiin, combined with ozocerite.

6. As a new article of manufacture, leather, waterproofed, stiffened and rendered non-slipping by impregnation with a heated, fluid mixture containing a solid' bitumen possessing at normal or somewhat higher temperatures a degree of elasticity comparable to that of elaterite combined with a fusible bitumen possessing high penetrative qualities.

7. As a new article of manufacture, leather, waterproofed, stifi'ened and rendered non-slipping by impregnation with elaterite combined with a fusible bitumen possessing high penetrative qualities.

8. As a new article of manufacture, leather, waterproofed, stiflened and rendered non-slipping by impregnation with elaterite combined with ozocerite.

9. As a new article. of manufacture, leather, waterproofed, stiffened and rendered non-slipping by impregnation with soluble in liquefied paralfins, and combined 10 elaterite, modified to render it substantially with ozocerite.

soluble in liquefied paraflins, and combined In testimony whereof I have afiixed my with afusible bitumen possessing highpenesignature, in presence of two witnesses.

trative qualities.

10'. As a new article of manufacture, WILLIAM SMITH leather, waterproofed, stiflenecl and ren- Witnesses: dered non-slipging by impregnation with C. F. BROWN, elaterite, modi ed to render it substantially P. W. Pnzzm'rr. 

